Year	Measure
1800	459.7
1820	459.7
1870	440.8
1913	634.2
1950	573.9
1951	589.9
1952	605.1
1953	621.2
1954	638.5
1955	654.2
1956	666
1957	676.3
1958	684.6
1959	690.4
1960	697
1961	708.2
1962	772
1963	769.5
1964	780.9
1965	764.7
1966	749.4
1967	637.1
1968	609.9
1969	644.6
1970	641.1
1971	657.7
1972	699.5
1973	729.2
1974	683.3
1975	619.2
1976	705.9
1977	713.5
1978	702.7
1979	693.4
1980	660.4
1981	668.8
1982	707.2
1983	729.5
1984	777.1
1985	805.2
1986	809.9
1987	820.8
1988	851.4
1989	868.8
1990	893.9
1991	927.1
1992	989
1993	1049
1994	1122
1995	1208
1996	1300
1997	1386
1998	1446
1999	1496
2000	1578
2001	1667
2002	1764
2003	1872
2004	1997
2005	2142
2006	2289
2007	2454
2008	2578
2009	2683
2010	2831
2011	2962
2012	3074
2013	3196
2014	3324
2015	3460
2016	3604
2017	3757
2018	3916